Preparation and Characterizations of Antibacterial Iodine‐Containing TiO ₂ Nanotubes Composite Coatings on Pure Ti

A two‐step electrochemical method was employed to fabricate iodine‐containing TiO ₂ nanotubes composite coatings on pure Ti, with the objectives of enhancing coating‐substrate adhesion and antibacterial performance. TiO ₂ nanotubes were synthesized via anodic oxidation followed by iodine electrodeposition in 0.2% povidone‐iodine solutions without KI and with varying concentrations of KI, respectively. The samples were characterized via SEM, EDS, and XPS. The coating‐substrate adhesion, antibacterial activity, and cytotoxicity were systematically evaluated. The results indicate that KI addition enhances the electrical conductivity of the electrolyte and thus accelerates iodine deposition, while excess I ⁻ leads to damage of nanotubular structure. The electrodeposited iodine species primarily exist in the forms of I ₃ ⁻ , I ₂ , and pentavalent iodine. The TiO ₂ nanotubes retard the iodine release rate. With increasing KI concentration, the coating‐substrate adhesion first increases and then decreases. The sample fabricated in the electrolyte with 0.05% KI achieves the maximum adhesion (28.7 ± 1.5 N). This optimal sample demonstrates antibacterial rates of 88.7% and 92.7% against E. coli and S. aureus , respectively while displaying negligible cytotoxicity. This two‐step electrochemical approach for fabricating iodine‐containing TiO ₂ nanotubes composite coatings serves as a viable surface modification strategy for Ti implants, yielding antibacterial coatings with substantial clinical potential.